Variable transmission is widely used in bike, electric bike, automobile, cloth rolling machine, and paper rolling machine. These variable transmissions generally use gear variable transmission structure or eccentric clutch structure. Gear variable transmission realizes gear shifting through gear transmission by using different sizes of gears. This transmission method causes loud noise and friction by the impact of gears. It is not suitable for long term and high efficient usage.
Chinese Patent No. 92105836.5 discloses a sliding block eccentric clutch of a stepless transmission. As shown in FIGS. 7 and 8, the stepless transmission 4 includes fixing tube 41, supporting tube 42, shaft 425, clamps 431,432, spring spreader 433, sliding rod 44, U-shape motion actuating rack 45, wire-tying bolt 451, connecting parts 452, ball bearing 453, control parts 454, 455, and two ends 46, 461 of a steel wire. In operation, a user pulls the end 46 or 461 of the steel wire by a control handle. This in turn pulls control part 455, actuates control part 454, ball bearing 453, connecting parts 452, wire-tying bolt 451, as well as clamps 431, 432, slides clamps 431, 432 along sliding rod 44, and connects supporting tube 42 to slotted plate 1 so that relative movements of fixing tube 41 and clutch parts 2, 2a regulate the degree of eccentricity for controlling the transmission. This kind of transmission has complicated structures and requires manual operation. This kind of transmission cannot satisfy some conditions required to input power and regulate variable ratio according to load. For example, when a reel block of a cloth rolling machine is continuously rolling cloth, the load is increasing.